JP3337785B2 - Method for producing modified polytetrafluoroethylene - Google Patents
Method for producing modified polytetrafluoroethyleneInfo
- Publication number
- JP3337785B2 JP3337785B2 JP26701593A JP26701593A JP3337785B2 JP 3337785 B2 JP3337785 B2 JP 3337785B2 JP 26701593 A JP26701593 A JP 26701593A JP 26701593 A JP26701593 A JP 26701593A JP 3337785 B2 JP3337785 B2 JP 3337785B2
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- Prior art keywords
- temperature
- irradiation
- ptfe
- kgy
- radiation
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、耐放射線性（放射線照
射による破断伸びの劣化が抑制された並びに破断強度の
劣化が抑制された性能）に優れ、かつゴム特性を有する
改質ポリテトラフルオロエチレン（以下、ＰＴＦＥとい
う）の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified polytetrafluoroethylene having excellent resistance to radiation (performance in which the degradation of elongation at break due to irradiation with radiation and the degradation of fracture strength are suppressed) and rubber properties. The present invention relates to a method for producing ethylene (hereinafter referred to as PTFE).
【０００２】[0002]
【従来の技術】ＰＴＦＥは耐薬品性と耐熱性に優れたプ
ラスチックであり、従来、産業用、民生用樹脂として広
く利用されている。また、ＰＴＦＥは結晶性高分子であ
り、比較的硬度が高くゴム特性の低い樹脂であるが、室
温程度の低い温度においても容易に塑性変形する性質が
ある。しかしながら、放射線環境下での利用はＰＴＦＥ
が放射線に対して極めて感受性が高く、１ｋＧｙを超え
ると機械特性が低下することから、原子力施設等の放射
線環境下では利用できない樹脂であった。これは、ＰＴ
ＦＥの場合、放射線照射により分子切断が優先的に生
じ、結晶化が容易に進行してしまうことに因るものであ
る。2. Description of the Related Art PTFE is a plastic having excellent chemical resistance and heat resistance, and has been widely used as an industrial or consumer resin. PTFE is a crystalline polymer and is a resin having relatively high hardness and low rubber properties, but has a property of being easily plastically deformed even at a low temperature such as room temperature. However, use in the radiation environment is PTFE
Is extremely sensitive to radiation, and if it exceeds 1 kGy, its mechanical properties deteriorate. Therefore, this resin cannot be used in a radiation environment such as a nuclear facility. This is PT
In the case of FE, molecular breakage occurs preferentially by irradiation, and crystallization easily proceeds.
【０００３】ＰＴＦＥはこれまで放射線に対して典型的
な分解型プラスチックであり、耐放射線性（放射線照射
による破断伸びの劣化が抑制された並びに破断強度の劣
化が抑制された性能）の付与、及び低結晶性でゴム特性
の付与が原子力施設等の放射線環境下での利用やシー
ル、パッキング材料への用途から望まれていた。Until now, PTFE has been a typical decomposable plastic for radiation, and has been given radiation resistance (performance in which deterioration of elongation at break due to irradiation with radiation and deterioration of break strength are suppressed), and It has been desired to provide low crystallinity and rubber properties for use in a radiation environment such as a nuclear facility or for use as a seal or packing material.
【０００４】本発明者らはこのようなＰＴＦＥの問題点
を解決するために鋭意研究の結果、原料ポリテトラフル
オロエチレンの結晶融点以上の温度で酸素不存在下にお
いて１ｋＧｙ以上の電離性放射線を照射することによっ
て架橋反応を起こさせ、耐放射線性に優れたＰＴＦＥが
得られることを見いだした。さらに、得られたＰＴＦＥ
が低結晶性でゴム弾性を有することも見いだした。従っ
て、耐放射線のみならずゴム弾性を有するＰＴＦＥが得
られた。The present inventors have conducted intensive studies to solve such problems of PTFE. As a result, the present inventors have conducted irradiation of ionizing radiation of 1 kGy or more in the absence of oxygen at a temperature higher than the crystal melting point of the raw material polytetrafluoroethylene. By doing so, a crosslinking reaction was caused, and it was found that PTFE excellent in radiation resistance was obtained. Furthermore, the obtained PTFE
Was also found to have low crystallinity and rubber elasticity. Therefore, PTFE having not only radiation resistance but also rubber elasticity was obtained.
【０００５】しかしながら、この方法ではＰＴＦＥの初
期の結晶融点である３２７℃以上の温度で放射線照射を
続けると、架橋反応に加えて熱分解反応や解重合反応が
起こりモノマーがＰＴＦＥの表面から飛散し、重量が減
少してしまうという欠点があった。However, in this method, when radiation is continued at a temperature of 327 ° C. or higher, which is the initial crystal melting point of PTFE, a thermal decomposition reaction or a depolymerization reaction occurs in addition to a crosslinking reaction, and monomers are scattered from the surface of the PTFE. However, there is a disadvantage that the weight is reduced.
【０００６】[0006]
【発明が解決しようとする課題】上記問題点に鑑み、本
発明は、熱分解や解重合による重量減少を生ずることな
くＰＴＦＥを放射線改質する方法を提供することを目的
とする。SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a method for radiation-modifying PTFE without causing weight loss due to thermal decomposition or depolymerization.
【０００７】[0007]
【課題を解決するための手段】上記課題を解決すべく、
本発明によれば、ポリテトラフルオロエチレンの結晶融
点以上の温度で酸素不存在下において１ｋＧｙ以上の電
離性放射線を照射することにより、改質ポリテトラフル
オロエチレンを製造する方法であって、照射線量の増大
につれて、結晶融点以上の温度を保ちつつポリテトラフ
ルオロエチレンの温度を下げることを特徴とする前記方
法が提供される。Means for Solving the Problems In order to solve the above problems,
According to the present invention, there is provided a method for producing a modified polytetrafluoroethylene by irradiating ionizing radiation of 1 kGy or more in the absence of oxygen at a temperature not lower than the crystal melting point of polytetrafluoroethylene, comprising: The temperature of the polytetrafluoroethylene is lowered while maintaining the temperature at or above the crystalline melting point.
【０００８】放射線照射の方法は、照射時の酸化を防止
するため酸素不存在下、すなわち真空中、又は不活性ガ
ス、例えば窒素やアルゴン雰囲気において、結晶融点
（３２７℃）以上の温度で電離性放射線（γ線、電子
線、Ｘ線、中性子線、高エネルギーイオン、以下放射線
という）を照射する。照射温度については３４０℃〜３
５０℃前後の温度が望ましい。また、照射線量は全体で
１ｋＧｙから１０ＭＧｙの範囲であるが、特にゴム特性
の点からは２００ｋＧｙから５ＭＧｙが望ましい。この
条件での放射線照射により、ＰＴＦＥは架橋されゴム弾
性体となる。[0008] The method of irradiation is performed by ionizing at a temperature higher than the crystal melting point (327 ° C) in the absence of oxygen, that is, in a vacuum or in an inert gas such as nitrogen or argon to prevent oxidation during irradiation. Irradiation (γ-ray, electron beam, X-ray, neutron beam, high energy ion, hereinafter referred to as radiation) is applied. Irradiation temperature is 340 ° C-3
A temperature around 50 ° C. is desirable. The irradiation dose is in the range of 1 kGy to 10 MGy as a whole, but is preferably 200 kGy to 5 MGy from the viewpoint of rubber characteristics. Irradiation under these conditions causes the PTFE to crosslink and become a rubber elastic body.
【０００９】このように、ＰＴＦＥに、その結晶融点以
上の温度で真空又は不活性ガス中で放射線を照射すると
架橋するが、結晶融点は放射線の線量が増大すると低下
してくる。そこで、本発明においては、照射時のＰＴＦ
Ｅの温度を、照射線量に合わせて変化させ、熱分解や解
重合を抑制しつつ架橋を進める。即ち、照射線量の増大
につれてポリテトラフルオロエチレンの温度をその結晶
融点以上の温度を保ちつつ下げる。As described above, when PTFE is irradiated with radiation in a vacuum or an inert gas at a temperature equal to or higher than its crystal melting point, the PTFE is crosslinked. However, the crystal melting point decreases as the radiation dose increases. Therefore, in the present invention, the PTF at the time of irradiation is
The temperature of E is changed according to the irradiation dose to promote crosslinking while suppressing thermal decomposition and depolymerization. That is, as the irradiation dose increases, the temperature of polytetrafluoroethylene is lowered while maintaining the temperature equal to or higher than the crystal melting point.
【００１０】本発明においては、例えば、照射初期に
は、３２７℃以上、望ましくは３４０〜３５０℃に昇温
するが、その後、５０ｋＧｙ照射後では３２０〜３３０
℃、１００ｋＧｙ照射後では２９０〜３００℃、２００
ｋＧｙ照射後では２８０〜２９０℃、５００ｋＧｙ照射
後では２６０〜２７０℃、そして１ＭＧｙ照射後では２
３０〜２４０℃に温度を下げていく。In the present invention, for example, the temperature is raised to 327.degree. C. or more, preferably 340 to 350.degree. C. in the initial stage of irradiation, and thereafter, 320 to 330 after irradiation of 50 kGy.
C, after irradiation of 100 kGy, 290 to 300 C, 200
280-290 ° C. after kGy irradiation, 260-270 ° C. after 500 kGy irradiation, and 2 after 1 MGy irradiation.
Decrease the temperature to 30-240 ° C.
【００１１】ＰＴＦＥの温度を低下させる方法に特に制
限はなく、従来公知の如何なる冷却方法をも使用するこ
とができる。例えば、示差走査熱量計（ＤＳＣ）で用い
られているような装置を用いて液体窒素等の冷媒によっ
て冷却したり、系内に流通せしめる不活性ガスの温度を
徐々に下げて冷却することができる。The method for lowering the temperature of the PTFE is not particularly limited, and any conventionally known cooling method can be used. For example, cooled Te <br/> by a refrigerant such as liquid nitrogen using the apparatus as used in a differential scanning calorimeter (DSC), gradually lowering the temperature of the inert gas allowed to flow into the system Can be cooled.
【００１２】放射線が照射されるＰＴＦＥの形状には特
に制限はなく、如何なる形状のＰＴＦＥであっても改質
することができる。しかしながら、電子線照射の場合、
放射線を全体にわたって均一に照射できるという観点か
らは、シート状や板状の形状であることが好ましい。The shape of the PTFE to be irradiated is not particularly limited, and any shape of the PTFE can be modified. However, in the case of electron beam irradiation,
From the viewpoint that the radiation can be uniformly irradiated over the entirety, it is preferable that the shape be a sheet shape or a plate shape.
【００１３】本発明の方法により得られた改質ＰＴＦＥ
は、これまで使用が不可能であった放射線環境下での工
業材料として、また放射線滅菌可能な医療用具素材とし
ての利用が可能となる。今迄は、ＰＴＦＥから成る医療
用具は放射線滅菌ができなかったことから、蒸気、ある
いはガス滅菌に因っているが、滅菌の確実性の点から放
射線滅菌の利用が可能となる。また、得られた改質ＰＴ
ＦＥはゴム特性も備えることから、特に、耐熱、耐薬品
性を要請される機器類のシール材料やパッキング材料と
しての特性の著しい向上が期待できる。The modified PTFE obtained by the method of the present invention
It can be used as an industrial material under a radiation environment, which has been impossible to use, and as a radiation-sterilizable medical device material. Until now, radiation-sterilization of medical devices made of PTFE has not been possible, and it is due to steam or gas sterilization. However, radiation sterilization can be used from the viewpoint of sterilization certainty. In addition, the obtained modified PT
Since FE also has rubber properties, it can be expected that remarkable improvement in properties as a sealing material or a packing material for equipment requiring particularly heat resistance and chemical resistance can be expected.
【００１４】以下に実施例を挙げて本発明を具体的に説
明するが、本発明はこれらに制限されるものではない。Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
【００１５】[0015]
【実施例１】厚さ０．５ｍｍの市販のＰＴＦＥシートを
真空中（０．０１トル以下）において、３４０℃に加熱
して、２ＭｅＶの電子線を０．５ｋＧｙ／ｓの線量率で
照射した。照射１００秒後（線量５０ｋＧｙ）には、温
度は３５０℃まで上昇した。１００秒後に３３０℃、２
００秒後（線量１００ｋＧｙ）に３００℃となるように
ＰＴＦＥの温度を下げていった。ＰＴＦＥの温度はＰＴ
ＦＥの支持台（加熱板）に通ずる電気ヒーターの電流を
調節して制御した。５００ｋＧｙ照射したところで照射
を終了した。このときのＰＴＦＥの温度は２７０℃であ
った。この結果得られた改質ＰＴＦＥの重量は３％減少
していたが、ＰＴＦＥの架橋による結晶融点の低下及び
引張試験による破断伸びと強度の変化は３４０℃の一点
設定温度で電子線を照射したときの変化とほぼ同一であ
った。Example 1 A commercially available PTFE sheet having a thickness of 0.5 mm was heated to 340 ° C. in a vacuum (0.01 Torr or less) and irradiated with a 2 MeV electron beam at a dose rate of 0.5 kGy / s. . After 100 seconds of irradiation (dose of 50 kGy), the temperature rose to 350 ° C. After 100 seconds, 330 ° C, 2
After 00 seconds (dose of 100 kGy), the temperature of the PTFE was lowered to 300 ° C. The temperature of PTFE is PT
The current of the electric heater leading to the FE support (heating plate) was adjusted and controlled. The irradiation was terminated when the irradiation was performed at 500 kGy. At this time, the temperature of the PTFE was 270 ° C. Although the weight of the modified PTFE obtained as a result was reduced by 3%, the decrease in the crystal melting point due to the crosslinking of the PTFE and the change in the elongation at break and the change in the strength due to the tensile test were performed at 340 ° C. at a single point set temperature. The change was almost the same.
【００１６】これに対して、３４０℃の一点設定温度で
照射を５００ｋＧｙ（照射１００秒後のＰＴＦＥ温度は
３５０℃）まで行ったときのＰＴＦＥの重量は約１０％
減少していた。On the other hand, the weight of PTFE when the irradiation is performed up to 500 kGy (the PTFE temperature after 100 seconds of irradiation is 350 ° C.) at a set point temperature of 340 ° C. is about 10%.
Had decreased.
【００１７】[0017]
【実施例２】厚さ０．５ｍｍの市販のＰＴＦＥシートを
アルゴンガス気流中で、３４０℃に加熱して、２ＭｅＶ
の電子線を０．５ｋＧｙ／ｓの線量率で照射した。そし
て、２００秒照射（線量１００ｋＧｙ）するごとに１０
℃の割合でアルゴンガス気流の温度を低下させてＰＴＦ
Ｅの温度を下げた。この結果、２０００秒（線量１ＭＧ
ｙ）及び４０００秒（線量２ＭＧｙ）照射した後のＰＴ
ＦＥの温度はそれぞれ２４０℃と２１０℃であり、ま
た、重量減少はそれぞれ４％と９％であった。ＰＴＦＥ
の放射線架橋による結晶融点及び引張試験による破断伸
び及び強度の変化は照射時の温度変化にほとんど依存し
ていなかった。Example 2 A commercially available PTFE sheet having a thickness of 0.5 mm was heated to 340 ° C. in a stream of argon gas, and was heated to 2 MeV.
Was irradiated at a dose rate of 0.5 kGy / s. And every 200 seconds (dose 100 kGy)
The temperature of the argon gas stream is reduced at a rate of
The temperature of E was lowered. As a result, 2000 seconds (dose of 1 MG
y) and PT after 4000 seconds (dose of 2 MGy)
The temperature of the FE was 240 ° C. and 210 ° C., respectively, and the weight loss was 4% and 9%, respectively. PTFE
The changes in the crystal melting point due to radiation crosslinking and the elongation at break and the strength in the tensile test hardly depended on the temperature change during irradiation.
【００１８】[0018]
【比較例１】実施例２と同様の条件で、３４０℃の設定
温度のまま照射を継続した。その結果、ＰＴＦＥの減少
は、それぞれ３０％及び６０％であった。COMPARATIVE EXAMPLE 1 Irradiation was continued under the same conditions as in Example 2 with the set temperature of 340 ° C. As a result, the reduction in PTFE was 30% and 60%, respectively.
【００１９】また、ＰＴＦＥの重量の減少に伴い、ＰＴ
ＦＥシートの厚さが減少した。更に、重量減少が３０％
を超えると、ＰＴＦＥシートに皺が入り平滑でなくなっ
た。Further, with the decrease in the weight of PTFE,
The thickness of the FE sheet has decreased. Furthermore, weight loss is 30%
When it exceeded, wrinkles were formed on the PTFE sheet, and the sheet was not smooth.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 乙幡 和重 東京都新宿区高田馬場４丁目40番13号 株式会社レイテック内 (72)発明者 田畑 米穂 東京都中野区本町４−48−17、701号 (72)発明者 大島 明博 栃木県塩谷郡塩谷町道下822 (56)参考文献 特開 平７−118424（ＪＰ，Ａ) 特開 平６−116423（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C08J 7/00 - 7/18 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazushige Otohata 4- 40-13 Takadanobaba, Shinjuku-ku, Tokyo Inside Raytec Co., Ltd. (72) Yoneho Tabata 4-48-17, Honcho, Nakano-ku, Tokyo No. 701 (72) Inventor Akihiro Oshima 822 Michishita, Shioya-cho, Shioya-gun, Tochigi Prefecture (56) References JP-A-7-118424 (JP, A) JP-A-6-116423 (JP, A) (58) Field (Int.Cl. 7 , DB name) C08J 7/ 00-7/18
Claims (2)
以上の温度で酸素不存在下において１ｋＧｙ以上の電離
性放射線を照射することにより、改質ポリテトラフルオ
ロエチレンを製造する方法であって、 照射線量の増大につれて、結晶融点以上の温度を保ちつ
つポリテトラフルオロエチレンの温度を下げることを特
徴とする前記方法。1. A method for producing modified polytetrafluoroethylene by irradiating ionizing radiation of 1 kGy or more in the absence of oxygen at a temperature not lower than the crystal melting point of polytetrafluoroethylene, comprising the steps of: The above method, wherein the temperature of the polytetrafluoroethylene is lowered while maintaining the temperature at or above the crystal melting point as the temperature increases.
り、５０ｋＧｙ照射後の温度が３２０〜３３０℃であ
り、１００ｋＧｙ照射後の温度が２９０〜３００℃であ
り、２００ｋＧｙ照射後の温度が２８０〜２９０℃であ
り、５００ｋＧｙ照射後の温度が２６０〜２７０℃であ
り、そして１ＭＧｙ照射後の温度が２３０〜２４０℃で
ある、請求項１に記載の方法。2. The initial temperature of irradiation is 340 to 350 ° C., the temperature after 50 kGy irradiation is 320 to 330 ° C., the temperature after 100 kGy irradiation is 290 to 300 ° C., and the temperature after 200 kGy irradiation is 280. The method of claim 1, wherein the temperature after 500 kGy irradiation is 260-270 ° C and the temperature after 1 MGy irradiation is 230-240 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26701593A JP3337785B2 (en) | 1993-10-26 | 1993-10-26 | Method for producing modified polytetrafluoroethylene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26701593A JP3337785B2 (en) | 1993-10-26 | 1993-10-26 | Method for producing modified polytetrafluoroethylene |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07118423A JPH07118423A (en) | 1995-05-09 |
| JP3337785B2 true JP3337785B2 (en) | 2002-10-21 |
Family
ID=17438878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26701593A Expired - Lifetime JP3337785B2 (en) | 1993-10-26 | 1993-10-26 | Method for producing modified polytetrafluoroethylene |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3337785B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3348610A4 (en) * | 2015-09-07 | 2019-05-22 | Sumitomo Electric Fine Polymer, Inc. | Method for manufacturing polytetrafluoroethylene molded body, and polytetrafluoroethylene molded body |
| EP3348601A4 (en) * | 2015-09-07 | 2019-05-29 | Sumitomo Electric Fine Polymer, Inc. | Polytetrafluoroethylene molded body, and manufacturing method therefor |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3317452B2 (en) * | 1992-10-05 | 2002-08-26 | 株式会社レイテック | Modified polytetrafluoroethylene and method for producing the same |
| JP3566805B2 (en) * | 1996-04-11 | 2004-09-15 | 日本原子力研究所 | Sliding member |
| JP4639373B2 (en) * | 2000-05-26 | 2011-02-23 | 独立行政法人 日本原子力研究開発機構 | Radiation-modified polytetrafluoroethylene and method for producing the same |
| JP2002256080A (en) * | 2001-02-28 | 2002-09-11 | Japan Atom Energy Res Inst | Radiation-modified tetrafluoroethylene resin material and its production method |
| JP3730533B2 (en) * | 2001-05-02 | 2006-01-05 | 日本原子力研究所 | Modification method of fluororesin |
| JP4591508B2 (en) | 2005-10-31 | 2010-12-01 | ダイキン工業株式会社 | Polytetrafluoroethylene molding method, polytetrafluoroethylene molded article, crosslinkable polytetrafluoroethylene, polytetrafluoroethylene crosslinked powder, resin blend composition, and resin blend molded article |
| JP4846496B2 (en) * | 2006-09-14 | 2011-12-28 | 株式会社レイテック | Cross-linked polytetrafluoroethylene resin and method for producing the same |
| JP5529466B2 (en) * | 2009-08-31 | 2014-06-25 | 住友電気工業株式会社 | Transparent resin molded body and method for producing the same |
| JP5845597B2 (en) * | 2011-03-10 | 2016-01-20 | ダイキン工業株式会社 | Manufacturing method of fine structure |
| US10294339B2 (en) * | 2015-01-20 | 2019-05-21 | Daikin Industries, Ltd. | Method for producing modified molded article of fluororesin |
| RU2597913C1 (en) * | 2015-06-03 | 2016-09-20 | Общество с ограниченной ответственностью "Инновационные Фторопластовые Технологии" | Method for thermo-radiating treatment of polytetrafluoroethylene articles |
| RU2669841C1 (en) * | 2017-08-09 | 2018-10-16 | Сергей Витальевич Слесаренко | Method of obtaining polymer materials |
-
1993
- 1993-10-26 JP JP26701593A patent/JP3337785B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3348610A4 (en) * | 2015-09-07 | 2019-05-22 | Sumitomo Electric Fine Polymer, Inc. | Method for manufacturing polytetrafluoroethylene molded body, and polytetrafluoroethylene molded body |
| EP3348601A4 (en) * | 2015-09-07 | 2019-05-29 | Sumitomo Electric Fine Polymer, Inc. | Polytetrafluoroethylene molded body, and manufacturing method therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07118423A (en) | 1995-05-09 |
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